Tuning control apparatus



Nov. 9, 1948. 1... L. ROYAL 2,453,268

' TUNING CONTROL APPARATUS Filed May 16, 1946 I 2 Shee'ts-Sheet 1[zzpezzfir Zea/1e Z. Fgal Nov. 9, 1948. L. ROYAL 2,453,268

' TUNING CONTROL APPARATUS Filed May 16, 1946 I 2 Sheets- Sheet 2 r" IHIH IIHI Patented Nov. 9, 1948 TUNING CONTROL APPARATUS Leslie L. Royal,Chicago, Ill., assignor to Belmont Radio Corporation, Chicago, Ill., acorporation of Illinois Application May 16, 1946, Serial No. 670,107

18 Claims.

The present invention relates to control apparatus for radio receiversand more particularly to manually operable automatic tuners of themechanical type for such receivers.

Many types of modern radio receivers are provided with automatic tuningmechanisms. .In general, such automatic tuners comprise a series ofmanually actuated push buttons which enable the listener to selectivelytune in particular stations merely by pushing or actuating the pushbuttons. The receiver also includes manual means for tuning it to otherbroadcasting stations which are within its range in addition to thosefor which the automatic tuning arrangement, including the push buttons,is set. In one form of automatic tuner for radio receivers, a series ofvariably positioned cams are provided along the tuning shaft, one foreach of the push buttons. Suitable cam locking means are provided forholding these cams in their predetermined positions relative to thetuning shaft so that when a push button is actuated, the associated camis rotated with consequent rotation of the tuning shaft to apredetermined position corresponding to a particular station setting fork which the push button and associated cam have been adjusted or set. Inorder initially to set the automatic tuning arrangement or to change thesetting thereof, it is necessary to operate some means for unlocking aparticular cam to the tuning shaft so that relative movement betweenthis cam and the tuning shaft can be obtained. The present invention isparticularly concerned with a new and improved arrangement for lockingthe cams to the tuning shaft, which locking means may be operated in asimple manner without additional equipment to afford a new setting oradjustment and is so constructed that the unlocking of any particularcam does not unlock the other cams.

Accordingly, it is an object of the present invention to provide a newand improved automatic tuning mechanism which is simple and inexpensiveto manufacture, foolproof in operation, and satisfactory in everyrespect from the standpoint of the radio listener who operates thereceiver.

A further object of the present invention ,is to provide a new andimproved automatic tuner which can be set and reset merely bymanipulation of the tuning mechanism itself without the use of extratools and equipment.

A still further object of the present invention is to provide a new andimproved manually operated automatic tuner for radio receivers having aplurality of control elements on a rotary shaft with each controlelement adapted to be set or reset to a predetermined positionindependently of the other control elements and while maintaining suchcontrol elements in a fixed position on the rotary shaft.

Still another object of the present invention is to provide a new andimproved cam locking means for an automatic tuner for a radio receiveror transmitter which comprises means for axially moving the cam on thetuning shaft to unlock the frictional or holding means.

Further ob ects and advantages of the present invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize this invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

For a better understanding of the present invention, reference may behad to the accompanying drawings in which:

Fig. 1 is a perspective view of an automatic. tuning mechanism embodyingthe present invention;

Fig. 2 is a plan view partly in section of two of the push buttons ofFig. 1 and the associated mechanism including a portion of the tuningshaft;

Fig. 3 is a view taken along line 3-3 of Fig. 2;

Fig. 4 is a View similar to Fig. 3 showing the push button operated totune in the particular station which that push button controls;

Fig. 5 is an enlarged sectional view taken along line 55 of Fig. 3, and

Fig. 6 is an enlarged somewhat exaggerated view of a portion of Fig. 5to illustrate the frictional or holding means in the released position.

Although the present invention is applicable to various forms ofautomatic tuners, both for radio receivers and transmitters, it has beenspecifically illustrated in the drawings, as applied to an automatictuner for radio receivers.

Referring now to the drawings, there is illustrated a tuning mechanismor unit for a radio receiver which comprises a movable control elementor rotary tuning shaft H! which is suitably journalled in frame membersH and I2 which in turn are held in spaced relationship by side pieces orframe members 53 and I4. The rotary shaft 19, which is provided with alongitudinally extending keyway I5, is coupled or otherwise connected toa suitable resonant frequency changing means for tuning the radioreceiver to particular stations. In Fig. 1 of the drawings, thisresonant frequency changing means is illustrated 3 as a variablecondenser having a rotor portion ll rotatable through. an angle ofsubstantially 18% degrees with respect to a stator portion I8. It shouldbe understood that the resonant frequency changing means might equallywell comprise a variable inductance or the like. As illustrated, thevariable condenser 56 supported by a frame member-*fdf-astenedtothcframe'member IE. Rotation of the tuning shaft: i ll will cause thecapacitance of the variable condenser l6 to vary to producecorresponding changes in the tuning of the radio set to any desired.station within the of the receiver. To accomplish this tuning, the endof shaft it, remoteifrompthe condenser it, is provided with arsegmentalgear.

frame portion suitably fastened by welding or .i

the like to frame member H.

:In accordance with the now well known automatic mechanical tuningmechanisms forradio receiven's ortransmitters, the shaft H3 is alsocontrollable by a plurality of push buttons or-the. like wherebyqaalioular stations to which-thelistener frequently desires to listen may betuned .in merely r'by actuating for-1e of the push buttons whichautomatically \causcs the desired rotation to beimpartedito'shaft H1without further eifortv member which is moved in a: generally.longitudinal'dircction upon actuating "the push button.-

The present invention' is illustrated in connection witlrthe lattertypeof selector unit, whilethe other typeof selector unit i'sdisclosedand claimed in a co-pcnding Plensler-application, Serial y'No.6511636filed'Ii/Iarch Zjifidan'd assigned to the same assigneeas thepresent application. Itwill be understood that a tuning unit maycomprise a large number of push'buttons. depending upon the numberofstations to which theilistencr'frcquently desires the set to be'tuned.Tlie'tuning unit of Fig. 1 has been illustrated as having a portion"thereof including additional push buttons omitted. although three pushbuttons are specifically shown. "Since all 'of these push buttons areidentical, as are also the associated selector units, these selectorunits are designated by the reference numeral 2-5 with the associatedsubscript a, b, or 0. Accordingly, inFig. 1 of the drawings there areillustrated selector units 25a; 25b and 2513 respectively.The-corresponding portions :of these selector units describedhereinafter are designated by identical reference numerals withoutthe'subscript. As illustrated, each of the selector units 25 is providedwith a manually actuable portion'or push button 26. It will beunderstood that a radio receiver might have as few'as three or four pushbuttons or ten or twelve or more. The sole purpose of each individualselector unit 25 is to rotate the tuning shaft or movable controlelement I'll to a predetermined angularsetting, which setting isdifierent for each selector unit operated. each selector unit 25 isidentical in every respect, only one, namely the unit 25a, will bedescribed hereinafter.

In order that each of the selector units such as "25a. 25b and the like,described in greater *detail hereinafter, may cause a predetermined Inview of the fact that 70 aperturc portions for the flanges 28c and 23The 4 rotation of tuning shaft H? which is different for each selectorunit, each selector unit is adapted to engage a cooperating heartshapedcam or selecting member 2?. Normally, each selecting 5 member .orcontrol unit 21 is locked or retained against rotation relative to thetuning shaft IE) and the present invention i particularly concerncd'withnew and improved looking or holding together with simple means forlocking and unlocking the same, the unlocking mecha- :nism operatingonly on the particular cam or control unit filbeing reset or initiallyset.

In brief, selector unit 250: comprises a carriage or supportingmemberfitwhich is slidably mount- -cd consequently may be characterized as themain slide=member;to distinguish it from other slidable members to bedescribed hereinafter. Selector unit 256, also includes, in addition tothe carriage or main slide member 28, a linearly movable actuated orslidable member 29. More specifically, the carriage .member 28 isofoflat irregular shape best shownin Figs. 3 an'df l of'the drawings,and is ntegrally formed with a body portion 230; and extending fingerportion 28b an extensionficc' which is connected to the body portion2362.011 theopposite, side from finger portion 28b. .The' body portion28a is provided withanintegralflanged portion 280'. at the lower edgethereof and a flanged portion 282 at the upper edge thereof whichextends somewhat along ringer .281). The main body portion 28a is alsoprovided-near the outer edges thereof with in wardly facing l.--shapedapertures 33. Between the apertures 3t isa larger aperture 35intowhichextends an integral projecting portion 28 of mainbodyfportionfida. A suitable extension or cam meansfi'i extendslaterally from the finger 28b on theedge of fingerfilib opposite flange28c and adjacent Where. finger 28b joins body portion'zfla. 4.0 Thilateral extension (52 has a cam surface 32a, the purpose of Which willbecome apparent as thefollowing description proceeds.

The actuated or slidable member 29 comprises -a, generall J-shapedvmember having laterally extending portions zl and 2% at either sidethereof which are adapted to fit into the L- shaped apertures 30 ofcarriage memberZfi. Preferably one of the laterally extending flanges29a is of L-shaped configuration so that it may be inserted only intotheend of-aperture 39 having the right angled'extension, but fter it ismoved along the L-shaped opening, can no longer be separated fromcarriage 28 unless it is moved back into this same end of the L-shapedaperture 30. The U-shaped slidable member 29 is provided with anlntegralprojecting portion 290 so that when it is in interlockingengagement Withcarriage-member '23, a compression spring 33 may be supported as isclearly indicated in Figs. 3 and B9 4 from projections 28f and 290respectively. Whenactuated.memberfZQ-is assembled with carriage member'28 so that compression spring 33 biases the'lateral flanges 25b towardsthe end of L' shaped openings Shremote from the right angled extensionas shown in Fig. 3, the carriage member is adapted for mounting in theframe members l3 and M. The frame member is is provided with openings Mato accommodate the carriagamember 28; including laterally extending bythe end of flange 28c engaging with frame member I 3. A suitable tensionspring member 34 connected between finger 28b and the frame member l3normally biases the carriage 28 to the position shown in Fig. 3.

In order that the selector unit 25a may impart a predetermined rotationto shaft [0, the actuated or slidable member 29 is provided at one endthereof with a roller 35 which engages the frame member 4, as is shownin Figs. 2 and 3 of the drawings, to limit the outward movement ofcarriage 28. Preferably, however, the outward movement of carriage 28 islimited by cushion means on the radio cabinet not shown engaging the endof flange 28c. This roller is adapted to engage the periphery ofheart-shaped cam 21 to effect rotation of the cam and consequentlyrotation of the tuning shaft I to the position indicated in Fig. 4 ofthe drawings where the roller 35 is positioned in the low point of thecam periphery. Normally, the compression spring 33 holds the relativelymovable slidable members 28 and 29 in the relative positions shown inFigs. 3 and 4, even when suiiicient force is applied to push button 26fastened to the extension 280 of carriage 28 to rotate the cam 21 andassociated tuning shaft 10 from the position shown in Fig. 4 to theposition shown in Fig. 6 of the drawings.

In accordance with the present invention, each cam 21 is fastened tosuitable means such as a collar member 38 rotatably mounted on the shaftI0 and furthermore mounted for limited axial movement relative thereto.Collar member 38 is provided with a pair of annular flanges 38a and 38b,as is best shown in Fig. of the drawings. The cams 2'! may be fastenedto the collars 38 by any suitable means, such, for example, as by meansof the peened-over portion 39 of the collar 3B. The cam 21 andassociated collar 38 are so positioned on the tuning shaft In that thefinger 28b of the associated selector unit is slidable between theflanges 38a and 38b, respectively.

In order to hold or look cam 2! and its associated collar 38 to shaftl0, whereby rotation of cam 21 will cause rotation of shaft Hi, there isprovided a friction or holding means comprising a collar 40 havingsuitably fastened thereto a leaf spring 4|. This collar is suitablykeyed to the shaft ID as by a deformed portion 40a thereof extendinginto keyway l5 of the shaft. Suitable means are also provided so thatthe friction collar 40 and its associated leaf spring 4! are preventedfrom moving axially along shaft l0. Shaft ill, for example, may beprovided at spaced points with suitable sawcuts Illa therein forreceiving suitable stop members 42 in the form of U-shaped washers, oran other suitable means for holding the collar 40 in a fixed positionrelative to shaft I 0 may be provided.

To hold the cam 21 in a fixed position relative to the shaft [0, it isprovided with a recessed portion 210. into which the leaf spring member4! may extend. The periphery of the recess 21a corresponds to the arcdefined by the free end of the leaf spring 4| when the cam 21 is rotatedrelative thereto. To look the cam 21, or to render the friction meanscomprising the leaf spring 45 effective, a suitable compression spring43 axially positioned relative to tuning shaft l0 biases the collar 38and consequently, the cam 21 toward the leaf spring 4i. Spring 43 iscompressed between the associated stop member 42, inserted in the sawcutor narrow portion of reduced diameter Na in the shaft 10, and the collar38. As illusjustable relative to the tuning shaft iii through degreesand suitable stop portions 211) integral with the cam 21 and extendinglaterally therefrom may be provided for engagement with the leaf spring4|, thereby effectively limiting the amount of rotation of the cam 21relative to shaft ID to 180 degrees.

In order to release the holding or friction means which effectively lockthe cam. 2? to the shaft [0, the lateral extension 32 having the camportiol 32a, described above, is provided for each finger 28b. When thecarriage member 28 is moved to the position shown. in Fig. 4 of thedrawe ings, the slidable member 29 is prevented from moving further in alongitudinal direction toward the frame member i3 so that continuedpressure applied to the carriage 28 through the push button 26 causesthe compression of spring 33 until the cam surface 32a engages theflange 38a of the collar 38 to move this collar laterally or axiallywith respect to shaft l8, whereby the cam 21 also moves axially awayfrom the leaf spring 40. This is clearly shown in Fig. 6 where theposition of the leaf spring is exaggerated to show that it is completelyfree of the recessed portion 210: of cam 21. Actually, the cam 2'! neednot be moved axially to a sufficient extent so that the leaf spring doesnot even touch the cam 21'. All that is necessary is that the frictionaleffect he reduced sufficiently so that relative movement of the cam 21and tuning shaft if! may take place. With the parts moved to thepositions shown in Fig. 6 of the drawings, it is possible to rotate thetuning shaft Ill through manipulation of the tuning knob 23, wherebyrelative rotation of shaft if) and cam 21 will occur. When the correctstation is tuned in, the push button 26 is released permitting thecompression spring 33 to move the main carriage 28 laterally so that thecamming surface 32a frees the flange 38a from the collar 33, whereby thecam Zlmoves towards the leaf spring 4i and is locked relative to theshaft iii. The tension spring 34 furthermore returns the selector unitto the position shown in Fig. 3 of the drawings.

The operation of the selector unit 2511 to rotate a correspondingselecting member or cam and thereby rotate the tuning shaft It to apredetermined tuning position for the condenser it is apparent from thedescription included above. In setting a cam 27 to an originalpredetermined position or resetting it to a subsequent predeterminedposition, the push button 25 is actuated so thatthe selector unitassumes the position indi cated in Fig. 4 of the drawings, whereby thecam 21 is held in apredetermined position by the roller 35. When anadditional force is applied to the push button 26 in the same direction.as was applied to move it from the position shown in Fig. 3 to theposition shown in Fig. of the drawings, the compression spring 33 iscompressed and the lateral extending member 32 having the cammingsurface 32a engages the flange 38a of the collar 38 to move this collarand the cam 21! associated therewith axially along the shaft it] againstthe force of the biasing means 43 away from the frictionally holding orlocking means comprising theleaf spring 4 I. When this has ocaaecgaescurred, :the shaft 1-0 :is free -to"r:rotateirelative :to the cam 21.Accordingly-, the tuningshaft l and the associated condenser I 6"arermoved ;to a position corresponding toltheldesiredtuningposition'which wills-be indicated b-ya. suitablezdial"on the ,radio receiver not :shown. When .thispredetermined tuningposition has been established, push button 2-6 is. released-andthe-'springs-33 :and cause the 'selectoriunit to assume its initialpositionsshownin Fig. 3 whereby the-cam z'l i's again'held iii-locked:orfixedposition relative to the :shaft 10. Thereafter,-the push button:26 is merel-y'used to move the'selector uni-tfromlthe position shown inliigndof the-drawings to the position shown in Fig. 4 to tuneinthepre'determined station for which the cam 2'! is set unlessitisagain desired to resetithe cam 21 relative to the tuning shaft l9.

=Fromthe above description, it willbe apparent that the presentinvention provides-a simplified, sturdy, manually operable-tunerfora-radio receiver in which the tuning operations for initially settingor resetting the cam relative .to-the tuning shaft can be accomplishedmerely by actuating the push button and-associated selector unit itself.Furthermore, averypositive arrangement for lockingthe cam .or apluralityof cams to the tuning shaft which locking arrangement for any desiredcam may be released fin a simple manner. .In addition, the parts of thecontrol apparatus are simple to assembleand inexpensive tov manufacture.

.It will be apparent to those skilled in the-art that the presentinvention is not limited to the particular construction shown .butvarious changes and modifications may be made therein without departinfrom the spirit and scope thereof, and it is aimed in the appendedclaims to cover'all such changes and-modifications a lfall withinthetrue spirit and scope of the present invention.

I claim:

1. A control device for controllable apparatus including a rotary shaft,a control unitmounted on said .shaft for relative movement therewith andcapable of limited axial movement relative to said shaft, means forholding said control unitrin a predetermined fixed position on saidshaft, a selector unit for causing rotation of said control unit andsaid shaft as a unit including an actuating means, and means on saidactuating means engagingsaid control unit for causing limited axialmovement thereof to release said means "for holding said control unit sothat relativemovement between said control unitand-said shaft can beobtained.

2. -A control device for controllable apparatus including a rotaryshaft, a cam mounted on said shaft for relative movement therewith andcapable of :limited axial movement relative .to said shaft, means-forholding said cam ina predetermined fixed position onsaid shaft, aselector unit fortcausing rotation ofsaid cam and said shaft as a unitincluding an actuating meanaand'means onsaid actuating means engagingsaid cam for causing limited axial movement thereof-to release saidmeans for holding-said cam-so thatrelative movement between'said cam andsaid shaft can be'obtained. Y i

--3. Tuning apparatus .for a radio receiver :or transmitter including aframe, a rotary tuning shaft journalled in saidlframe, control means onsaid shaft including a'cam, meansfixed tosaid shaft engaging the side ofsaid'campmeans for biasing :said (Scam against vsaid -:last mentionedmeans to hold said'rcamin a-fixed position relative to "saidshaft,manually'operable meanslfor engaging the edge of said cam to causerotation ofxfsaid camrsand said shaft, and means associated with saidmanually operable means for moving said "cam in an axial directionalongksaid-shaft againstthe 'forceof said means for biasing'said camwhereby relative movement between said cam and said-shaft can beobtained.

4. Tuning :apparatus for a radio receiver :or

transmitter including a frame, a rotary tuning shaft journalled'in saidframe, control means on said shaft including a'cam, means fixed to'saidshaft including a leaf spring engaging the side-of i saidcam, means forbiasing saidcam againstgsaid leaf spring to hold said cam in a fixedposition relative to said-shaft, manually operable means for'engaging'the edge of said cam to cause rotation of said cam and said shaft, andmeans asso- ,ciated with said manually operable means for moving saidcam, in an axial direction along-said shaft against the'force of saidmeans'forbiasing said cam whereby relative movement between said cam andsaid shaft canbe obtained.

5. Tuning apparatus fora radio receiver or transmitter including aframe, a rotary tuning shaft'jcurnalled in said frame, control means'onsaid shaft-including a cam, means including a leaf spring fixed to saidshaft and engaging the side of said cam, means for biasing said camagainst said leaf spring to hold said camin'a fixed position relativeto. said shaft, manually 0perable means for engaging'the periphery ofsaid cam to cause rotation of said cam'and saidshaft as a unit,'andmeans including a 'camming-sur face associated with said manuallyoperable means for moving said cam in an axial direction along saidshaftagainst'theiforce ofsaid means for biasing said ca'm wherebyrelative movement betweensaidcam and'saidsha'ftrcan be obtained.

6. A controldevice fora radio receiver includ ing a "rotarytuningshaft,a cam mounted on said shaft for relative movement therewith,means permitting limited axial movement'of said cam relative tosaid'shaft, a spring means fixed'to said shaft, means 'for biasing said'camtowar'd said spring means'to'hold said camin a'fixed positionrelative to said'shaft, a selector unit for causing rotation of'said'cam and tuning shaft as a unit -upon operation thereof, and meanson said selector unit for causing axial movement of said camaway fromsaid spring means whereby the position 'of said cam relative-tosaidshaft maybe varied.

'7. A control 'device'for a radio receiver including a rotary tuningshaft, a cam mounted on said shaft for relative movement therewith,means permitting limited axial'movem'ent of said cam relative to saidshaft, a leaf spring means :fixe'd to said shaft, means for biasing theside of said cam into frictional engagement With said leaf spring meansto'hold'said cam in a fixed position relativeto-said shaft, aselector'unit'for engaging the periphery of said cam causing rotation ofsaid cam and tuning shaft as a unit, and means on said selectorunitfor'causing axial movement of said cam away from said leaf spring:means whereby the position of said camrelative to "said shaft maybe'varied.

8. :A'control device'for aradio-receiverincluding a rotary tuning shaft,a'cam mounted 'on said shaft for relative movement therewith, meanspermitting limited axial movement of said cam, a leaf spring fixed tosaid shaft, means for biasing :said -:ca-1n in an axial direction:toward said leaf spring into frictional engagement therewith to holdsaid cam'in a fixed position relative to said shaft, a selector unitincluding a main carriage member and an actuated member slidably relatedto said carriage member, means on ceiver or transmitter a tuning shaft,va cam mounted on said shaft for both fixed or relative movementtherewith, frictional means for locking said cam and said shaft inanfixed relative position, actuating means which when actuated apredetermined amount causes rotation of said cam and tuning shaft as aunit, and means adapted to engage said cam upon further actuation ofsaid actuating means in the same direc-,

tion for causing limited axial movement of said cam relative to saidshaft.

10. In a tuning control device for a radio receiver or transmitter, atuning shaft, a cam mounted on saidshaft forboth fixed or T812412.

tive movement therewith, actuating means which when actuated apredetermined amount causes rotation of said cam and tuning shaft as aunit, and means adapted to engage said cam upon further actuation ofsaid actuating means in the same direction for causing limited axialmovement of said cam relative to said shaft.

11. A frequency control device as for a radio receiver or transmitter,including a movable control element for varying either the inductance orcapacitance of a tuning circuit, a selecting member carried on saidcontrol element for both fixed or relative movement therewith, africtional means for locking said member and said element in a fixedrelative position, actuating means movable in a given direction forapplying a first force to said selecting member in said given directionto move said element and said member as a unit to a positionpredetermined by the relative positions of said element and said member,and means carried by said actuating means and operable in response tofurther movement of said actuating means in said given direction forapplying a second force to said selecting member substantiallyperpendicular to said given direction to move said selecting memberrelative to said frictional means.

12. A frequency control device as for a radio receiver or transmitter,including a movable control element for varying either the inductance orcapacitance of a tuning circuit, a selecting member carried on saidcontrol element for both fixed or relative movement therewith, actuatingmeans for app-lying a first force to said selecting member in thedirection of movement of said means to move said element and said memberas a unit to a position predetermined by the relative positions of saidelement and said member, and means carried by said actuating means andoperable in response to further movement of said actuating means in thesame direction as for moving said element and member as a unit forapplying a second force to said selecting member substantially at rightangles to the direction of said first force.

v 13. A frequency control device as for a radio receiver or transmitter,including a rotatable control element for varying either the inductanceor capacitance of a tuning circuit, a selecting member carried on saidcontrol element for both fixed or relative movement therewith,frictional means for locking said member and said element in a fixedrelative position, actuating means to rotate said element and saidmember as a unit to a position predetermined by the relative positionsof said element and said member, and means carried by said actuatingmeans engaging said selecting member and operable in response to furthermovement of said actuating means in the same direction as for rotatingsaid element and member as a unit to cause axial movement of saidselecting member relative to said rotatable control element.

14. A control device for a radio receiver including a rotary tuningshaft, a cam and associated collar member mounted on said shaft forrelative movement therewith, means permitting limited axial movement ofsaid cam, a leaf spring fixed to said shaft, means for biasing said camin an axial direction toward said leaf spring into frictional engagementtherewith to hold said cam in, a fixed position relative to said shaft,means on said cam and engageable with said leaf spring for limiting therelative rotation between said cam and said leaf spring, a selector unitincluding a main carriage member and an actuated member slidably relatedto said carriage member, means on said actuated member for engaging theperiphery of said cam upon the application of force to said selectorunit to cause rotation of said cam and tuning shaft as a unit, and cammeans on said carriage member for engaging said collar member to causeaxial movement of said collar member and cam away from said leaf springupon the continued application of a force to said selector unitfollowing rotation of said cam and tuning shaft as a unit whereby theposition of said cam relative to said shaft may be varied.

15. A control device for a radio receiver including a rotary tuningshaft, a cam and associated collar member mounted on said shaft forrelative movement therewith, means permitting limited axial movement ofsaid cam, a leaf spring fixed to said shaft, means for biasing said camin an axial direction toward said leaf spring into frictional engagementtherewith to hold said cam in a fixed position relative to said shaft, aselector unit including a main carriage member and an actuated member topredetermined relative positions, means on said actuated member forengaging the periphery of said cam upon the application of force to saidselector unit having a magnitude insufficient to produce relativemovement between said carriage and actuated members to cause rotation ofsaid cam and tuning shaft as a unit, and means on said carriage memberfor causing axial movement of said cam away from said leaf spring uponthe application of a force to said selector unit sufficient to compresssaid compression spring means and cause relative movement between saidcarriage and actuated members following rotation of said cam and tuningshaft as a unit whereby the position of said cam relative to said shaftmay be varied.

l6. Tuning apparatus for a radio receiver or transmitter including 'arotary tuning shaft, a plurality of control units mounted on said shaftfor relative movement therewith and capable of independent limited axialmovement relative to.

mana

'11 u said shaft, individual 11183115101 holding said'control units inpredetermined fixed positions: on said shaft, actuating meansindividually associated With said control unitsufor causing; rotationoft said control units, andmeans on each of; said actuating meansengaging the associated control' unit for causing limited axial movementthereof in response to movement of saidactuatingmeans to release said'holding means for said associated control unit, movement. of each individual actuating means being entirely ineffective to release saidholding means for said. control units other thansaidcontrol unitassociated with said individual actuating means.

17. A frequency control device for a radio receiver or transmitterincluding a movable control'element for varying either the inductance orcapacitance of'a tuning circuit; a plurality of selector members carriedon said control element for both fixed or relative movement therewith,-

individual means for holding said selector-members in predeterminedfixed positions witl-i respect to saidcontrol element, actuating meansindividually associated with said selector membars-for causing movementof said members and;

said-control element as aunit, and means oneach of said actuating meansengagingtheassociated selector member for releasing said holding meansforsaid associated selector member, movement of each individualactuating means being entire1y30 2320;893

which; when actuated a; predetermined: amount causes rotation of:saidicams :and .tun-ingishafttas a. unit, meanscomeachvindiv-idualaotuaitingimeans engagingxthe assooiatedacamzuponifurtheractuation of;said: individual-means inthe same: direction for. causing, limitedtaxial: movement 1 of? said cam relative to :said shaft; movement ofeach individual actuating meanssheing entirely ineffective to causeaxial movement: ofr -saidscamsi.other than; said cam associatedwith-usaidxindividual actuating means;

REEERENGES -.GI.TED

The following-references" are of record in the file of this patent:

UNITE-ESTATES PATENTS,

Name l Number Date Schwarz eta1: June 1; 1943

